SQL Server User Group: SQL Injection Attacks

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Examples

The examples were run against a copy of the Adventure Works database.

• Basic Demo (ASP.NET MVC / C# / Visual Studio 2010)
• Second Order Demo (WinForms / C’# / Visual Studio 2010)

Required Tables

For the Second Order Demo you need the following table added to the Adventure Works database:

CREATE TABLE [dbo].[FavouriteSearch](
	[id] [int] IDENTITY(1,1) NOT NULL,
	[name] [nvarchar](128) NOT NULL,
	[searchTerm] [nvarchar](1024) NOT NULL
) ON [PRIMARY]

GO

Stored Procedure with dynamic SQL

This is the stored procedure from the last demo which shows the Stored Procedure dynamically building a SQL statement that is susceptible to a SQL Injection Attack.

CREATE procedure [dbo].[SearchProducts]
(
  @searchId int
)
AS
BEGIN

  DECLARE @searchTerm NVARCHAR(1024)
  SELECT @searchTerm = searchTerm FROM FavouriteSearch WHERE id = @searchId

  DECLARE @sql NVARCHAR(2000) =
  'SELECT ProductID, Name, ProductNumber, ListPrice
  FROM Production.Product
  WHERE DiscontinuedDate IS NULL
  AND ListPrice > 0.0
  AND Name LIKE ''%'+@searchTerm+'%''';

  EXEC (@sql);

END

Slide Deck

The slide deck is available for download.

Further Reading

During the talk I mentioned this lesson from history (why firewalls are not enough), I also showed XKCD’s famous “Bobby Tables” cartoon, and also a link to further information on dynamic SQL in Stored Procedures. More information about the badly displayed error messages can be found amongst two blog posts: What not to develop, and a follow up some months later.

I wrote an article on SQL Injection Attacks that you can read here.

Image may be NSFW.
Clik here to view.

Image may be NSFW.
Clik here to view.